How to put SwiftUI button into NSToolbar?

Question

This is how SwiftUI can be inserted into NSToolbar using an accessory view controller:

import SwiftUI
import PlaygroundSupport

var hostingView          


        

Answer 1

The way I eventually handled it (making it work also when the user makes the window full screen AND regardless of the height* of the content) is below. Note that I'm using Toolbar view in an NSHostingView within NSTitlebarAccessoryViewController of a macOS app built with most recent Xcode version (obviously, on macOS Catalina).

Important things: *you still need to setup a fixed height for the frame (but at least you won't rely to the "variable" -7) and offset to top by half of the actual height ONLY when there is safe area top inset (in full screen mode, apparently, it isn't) and therefore GeometryReader is a must:

struct Toolbar : View {
    var body: some View {
        GeometryReader { geometry in
            VStack {
                Text("1st row")
                Text("2nd row")
            }
            .offset(y: geometry.safeAreaInsets.top > 0 ? -geometry.size.height / 2 : 0)
        }
        .frame(height: 42)
    }
}

and where window is created:

let toolbar = NSHostingView(rootView: Toolbar())
toolbar.frame.size = toolbar.fittingSize
let toolbarController = NSTitlebarAccessoryViewController()
toolbarController.view = toolbar
window.addTitlebarAccessoryViewController(toolbarController)